Alternate Gateway in TCP/IP SMTP service not working as expected

[Camiel]

Hello,

I need my SMTP server to:
1. accept incoming SMTP messages from any source
2. forward these to a second SMTP server (mgate.nic.agro.nl) if it's not a mail for the local system (pd12.minlnv.agro.nl)

So, I've set up my SMTP service as follows:

TCPIP> sho conf smtp /full

SMTP Configuration
Options
Initial interval: 0 00:30:00.00 Address_max: 16 NOEIGHT_BIT
Retry interval: 0 01:00:00.00 Hop_count_max: 16 RELAY
Maximum interval: 3 00:00:00.00 TOP_HEADERS

Timeout Initial Mail Receipt Data Terminate
Send: 5 5 5 3 10
Receive: 5

Alternate gateway: MGATE.NIC.AGRO.NL
General gateway: not defined

Substitute domain: HIDDEN, MINLNV.AGRO.NL
Zone: PD12.MINLNV.AGRO.NL

Postmaster: TCPIP$SMTP
Log file: SYS$SPECIFIC:[TCPIP$SMTP]TCPIP$SMTP_LOGFILE.LOG

Generic queue Queues Participating nodes

TCPIP$SMTP_PD12_00 2 PD12
TCPIP>

However, when I send a message to an external e-mail address, the SMTP server on the local system will try to talk directly to the receiving SMTP server, ignoring the alternate gateway, which fails because of our firewall configuration, as shown by the return-message shown here:

MailEnable: Message delivery has been delayed.

Message is waiting at minlnv.agro.nl for delivery to dpmail04.doteasy.com.

Reason: Mail Server for camicom.com could not be contacted at this time. MailEnable will keep trying to deliver this message and will notify you of any progress.

I've been going through the manuals forward and backward, but I can't find what I'm doing wrong...

Suggestions, anyone?

Thanks,

Camiel.

[Camiel]

A little addition:

When I send e-mail to a foreign domain using the OpenVMS Mail utility, it works fine. The problem occurs only with e-mails coming in on the SMTP port.

Secondly, the configuration isn't really clear in my original message, so I'll attach it as a text file.

Camiel.

[Willem Grooters]

Camiel,
One reason I can think of is that the address of the remote (external) mailserver can be translated so the effect would be that SMTP will contact that server directly - there is no need to use the alternate.
I see that with my own server - if my VMS box cannot track the IP address on "the other side", it will use the ISP's.
You could think of using the general gateway instead, but in that case, I think that all messages will go that way.
Since you have defined RELAY you might be able to achive what you want by playing with settings in the SMTP configuration file.

Willem

[Michael Yu_3]

Hi Camiel,

Alternate gateway is used only if the local host could not deliver the mail itself.

General gateway is used for non-smtp mails.

In your case, the mail can be delivered by your host, so there is no need to use the alternate gateway.

Thanks and regards.

Michael

[Joseph Huber_1]

Define/system TCPIP$SMTP_ALTGATE_ALWAYS 1

and put local systems into
SYS$COMMON:[TCPIP$SMTP]TCPIP$SMTP_LOCAL_ALIASES.TXT
.

[Camiel]

Thanks, Willem and Michael.

I understand now that the problem is caused because the VMS server "knows" the IP address of the external mail servers, thanks to our DNS system, but then can't actually contact them thanks to our firewall.

Thanks also to Joseph, I'm going to talk to my system administrator, and get him to try your solution. I'll let you know if this works for us.

Camiel.

[Camiel]

I tried Joseph's suggestion, and restarted the SMTP service, but the behaviour hasn't changed. Any other suggestions, anyone?

Camiel.

[Ian Miller.]

If you smtp logging it may tell you what its doing.

DEFINE/SYSTEM TCPIP$SMTP_LOG_LEVEL 4

I think

[Michael Yu_3 · Accepted solution]

Hi Camiel,

Have you defined tcpip$smtp_local_alias_only as well?

Thanks and regards.

Michael